The movie based on the British TV hit Downton Abbey is nearing its production start, after Deadline broke the story in July that Focus Features was moving forward on a long-in-the-works feature film reuniting the main cast of the most nominated non-U.S. TV series in the history of the Emmys.

Focus and producer Carnival Films said today that Oscar nominee Imelda Staunton, Geraldine James, Simon Jones, David Haig, Tuppence Middleton, Kate Phillips and Stephen Campbell Moore have joined the cast. The original cast including Maggie Smith, Michelle Dockery and Hugh Bonneville are already set to reprise their upstairs/downstairs roles.

Michael Engler is directing the film, which was written by series creator Julian Fellowes. Fellowes is producing alongside Gareth Neame and Liz Trubridge. Brian Percival, who directed the series’ pilot, is now executive producing the movie with Nigel Marchant.

Downton Abbey followed the lives of the Crawley family and the servants who worked for them for six seasons on the UK’s ITV and PBS’ Masterpiece in the U.S., garnering a massive worldwide following and helping to kick-off the so-called new golden age of television, all while making period drama chic again. The series won three Golden Globes, 15 Primetime Emmys (out of 69 nominations in total) and a special BAFTA.

The movie is a Carnival Films production, with Focus Features and Universal Pictures International distributing.